Geothermal power is the power that we obtain from the Earth’s heat, precisely form the inside of the Earth. This heat power is used to generate electricity in Geothermal power plants, which work by heating up water with this heat, and by turning it into steam, making turbines to rotate and power the generators.
How do we get energy from this power source?
To get energy form Geothermal power it is needed a big generator with turbines, as the one used in nuclear power plants. It’s also needed a lot of water, and a big construction of pipes that take the water up and down to the rock inside the earth where magma can be found. This water has to go down through this pipes, and it has to be heated up by the magma, so that it will turn into steam. The steam gets compressed, while it goes up back to the power plant. When it gets there the pressure of the steam is big enough to make the turbine turn, and power a generator. This steam then release, and some of cools down and turns into water, so it can be pumped sown to the hot rocks again.
For Geothermal electricity, we don’t need to create the heat, since it’s already there, once the Earth’s rocks that are just a few kilometers down have a temperature of over 250 degrees Celsius. Enough to overheat water, turning it into steam very fast. This resource is from the earth's rocks, which at a certain depth.
Effects of the power generation on the environment:
The impact of the Geothermal power is not very big, it just pollutes the air a bit with steam, an uses a lot of water, which is a precious resource, and for it not to be wasted it's necessary to use water that isn't clean or fresh.
The cost for builidng a geothermal power plant varies a lot with the size and the quantity of energy to be produced. The cost of the power form the geothermal power plant is of about 4.5 to 7.3 cents per kilowatt-hour (this is the operation cost, since nothing else than the rocks heat is needed to heat up the water the cost is very low). the energy produced per power plant depends of the power plant. To build a 20MW power plan it costs around $55,000,000.00 (55 million dollars), depending of the location this cost can change to between 23 and 60 million dollars.
The capacity of the Geothermal power field (not the power plant, the place where there are these power plant) can be over 1000MW.
The best location for a power plant is a place where the hot rocks aren't too deep into the Earth, so it's easier to get to them.
What is the lifetime of the generator?
The lifetime isn't well defined but according to some articles about projects the lifetime is expected to be from 30 to 40 years.
The Advantages...
No pollution is made.
Doesn't contribute to the greenhouse effect.
Power stations don't need much space and don't have big impact on the environment.
No fuel is needed.
After building the power plant, the energy is almost free (has a low cost) .
It needs energy to run water pumps, but this is the same electricity that is being generated by the power plant.
...and Disadvantages
There aren't many places to buid a geothermal power plant. You need suitable types of rock, so that they are hot, and easy to drill through.
The "geothermal site" (place where there are the hot rocks) may cool down and stay like that.
Dangerous gases an minerals may come form underground, and it might be hard to get free of them.
Construction of the power plant may affect land stability on the sorrounding region.
The two biggest dangers of the geothermal power plant are listed above on the disadvantages.
Why is it renewable?
Geothermal power is renewable, because it's already there, and you don't need to create this energy, you just have to use it at the appropriate form. And also because this energy will be there for a very, very long time, if we don't cool down those rocks on purpose.
Curiosities and additional information:
Today, United States is the country with the greatest geothermal energy production.
The largest steam field in the world is The Geysers , which are located 72 miles (116 km) north of San Francisco, California.
Geothermal power should have a significant role, being very important on the future of power generation.
What is Geothermal Power?
Geothermal power is the power that we obtain from the Earth’s heat, precisely form the inside of the Earth. This heat power is used to generate electricity in Geothermal power plants, which work by heating up water with this heat, and by turning it into steam, making turbines to rotate and power the generators.
How do we get energy from this power source?
To get energy form Geothermal power it is needed a big generator with turbines, as the one used in nuclear power plants. It’s also needed a lot of water, and a big construction of pipes that take the water up and down to the rock inside the earth where magma can be found. This water has to go down through this pipes, and it has to be heated up by the magma, so that it will turn into steam. The steam gets compressed, while it goes up back to the power plant. When it gets there the pressure of the steam is big enough to make the turbine turn, and power a generator. This steam then release, and some of cools down and turns into water, so it can be pumped sown to the hot rocks again.
For Geothermal electricity, we don’t need to create the heat, since it’s already there, once the Earth’s rocks that are just a few kilometers down have a temperature of over 250 degrees Celsius. Enough to overheat water, turning it into steam very fast. This resource is from the earth's rocks, which at a certain depth.
Effects of the power generation on the environment:
The impact of the Geothermal power is not very big, it just pollutes the air a bit with steam, an uses a lot of water, which is a precious resource, and for it not to be wasted it's necessary to use water that isn't clean or fresh.
The cost for builidng a geothermal power plant varies a lot with the size and the quantity of energy to be produced. The cost of the power form the geothermal power plant is of about 4.5 to 7.3 cents per kilowatt-hour (this is the operation cost, since nothing else than the rocks heat is needed to heat up the water the cost is very low). the energy produced per power plant depends of the power plant. To build a 20MW power plan it costs around $55,000,000.00 (55 million dollars), depending of the location this cost can change to between 23 and 60 million dollars.
The capacity of the Geothermal power field (not the power plant, the place where there are these power plant) can be over 1000MW.
The best location for a power plant is a place where the hot rocks aren't too deep into the Earth, so it's easier to get to them.
What is the lifetime of the generator?
The lifetime isn't well defined but according to some articles about projects the lifetime is expected to be from 30 to 40 years.
The Advantages...
No pollution is made.
Doesn't contribute to the greenhouse effect.
Power stations don't need much space and don't have big impact on the environment.
No fuel is needed.
After building the power plant, the energy is almost free (has a low cost) .
It needs energy to run water pumps, but this is the same electricity that is being generated by the power plant.
...and Disadvantages
There aren't many places to buid a geothermal power plant. You need suitable types of rock, so that they are hot, and easy to drill through.
The "geothermal site" (place where there are the hot rocks) may cool down and stay like that.
Dangerous gases an minerals may come form underground, and it might be hard to get free of them.
Construction of the power plant may affect land stability on the sorrounding region.
The two biggest dangers of the geothermal power plant are listed above on the disadvantages.
Why is it renewable?
Geothermal power is renewable, because it's already there, and you don't need to create this energy, you just have to use it at the appropriate form. And also because this energy will be there for a very, very long time, if we don't cool down those rocks on purpose.
Curiosities and additional information:
Today, United States is the country with the greatest geothermal energy production.
The largest steam field in the world is The Geysers , which are located 72 miles (116 km) north of San Francisco, California.
Geothermal power should have a significant role, being very important on the future of power generation.
Sources:
Wikipedia - http://en.wikipedia.org/wiki/Geothermal_power
Energy Resources - http://home.clara.net/darvill/altenerg/geothermal.htm
Union sf soncerned scientists -http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-geothermal-energy-works.html
Goethermal Energy Association - http://www.geo-energy.org/aboutGE/powerPlantCost.asp
Illinois Institute of Technology - http://www.iit.edu/~ipro348s07/research.html
By: Pedro Alexandre Tonet Fleig
Grade 7
Grade 7 DT Projects 08